1. Field of the Invention
The present invention relates to a power tool, in particular, a circular saw with an eccentrically driven working tool, in particular, a circular saw blade. The power tool includes a housing and a motor located in the housing. The power tool further includes a roller device supported on the housing and having at least two roller pairs spaced from each other and each having a first roller and a second roller. The first and second rollers of both roller pairs engage opposite sides of the working tool. At least one of the rollers of at least one roller pair is rotatable by the motor for driving the working tool.
2. Description of the Prior Art
In power tools of the type described above, as a rule, one roller pair is used for driving the working tool, with the working tool being clamped between one roller, which functions as a drive roller, and another, counter-pressure roller. The at least one another roller pair serves for guiding the working tool and for absorption of radial and axial forces generated during operation of the power tool. To this end, the at least one another roller pair has two rollers which function as guide rollers and which are freely rotatable and, during the operation of a power tool, roll over opposite sides of the working tool.
German Publication DE 21 61 489 discloses a power tool with a circular working tool. The tool has a drive roller pair with a drive roller and a counter-pressure roller, with the counter-pressure roller being biased, in different embodiments, with a spring element against the working tool. The tool further includes a guide roller pair, the guide rollers of which are spaced from the drive roller pair and are secured, with a possibility of rotation, on the circular blade housing.
The roller device of this German publication insures a stable guidance of circular working tool, during the operation against axial and radial displacements.
A drawback of the known power tool consists in that with the guide rollers being fixedly secured on the blade housing, wear of the guide rollers, which increases during their service life, cannot be compensated. As a result, the precision of the working tool guidance becomes reduced with time, which reduces the operational life of the tool. In addition, because of the fixed support of the guide rollers, the replacement of the working tool in the known power tool requires a relatively large amount of time and is very elaborate.
Accordingly, an object of the present invention is to provide a power tool of the type described above and in which the above-discussed drawbacks of the known tool are eliminated.
Another object of the present invention is to provide a power tool of the type discussed above and which would insure a rapid and easy replacement of the working tool.